Nanocatalysts, preparation methods and applications for reforming carbon dioxide and methane to syngas

ABSTRACT

The catalyst in this present application includes a support and an active component dispersed on/in the support; wherein the support is at least one selected from inorganic oxides and the support contains macropores and mesopores; and the active component includes an active element, and the active element contains an iron group element. As a high temperature stable catalyst for methane reforming with carbon dioxide, the catalyst can be used to produce syngas, realizing the emission reduction and recycling utilization of carbon dioxide. Under atmospheric pressure and at 800° C., the supported metal catalyst with hierarchical pores shows excellent catalytic performance. In addition to high activity and good selectivity, the catalyst has high stability, high resistance to sintering and carbon deposition.

TECHNICAL FIELD

The present application refers to a catalyst, preparation method andapplication for reforming carbon dioxide and methane to syngas,belonging to the field of chemical engineering.

BACKGROUND

Coal, petroleum and natural gas are three major fossil energy sources.In China, coal resources are abundant, while in recent years thepollution of the atmosphere, soil and groundwater has become more andmore serious in the process of coal mining and utilization, limiting itsmassive use. However, the Chinese petroleum reserves are low and must beimported, leading to high usage cost. In recent years, with Chineseshale gas resource leaping to the world front row, the development andutilization of natural gas has taken more and more attention. TheChinese government has introduced policies to encourage thecomprehensive and high-efficiency utilization of natural gas. Thehigh-efficiency utilization of natural gas has risen to the nationalstrategic altitude. In addition to direct usage of natural gas as afuel, methane, which is a main component in natural gas, can beconverted to chemical products with high added value by efficientconversion of syngas. For instance, methane can be used to produceammonia and methanol for large tonnage needs, and methane also can beused to produce the intermediates of liquid fuels, such as olefins,aromatics and the like.

At present, syngas is industrially produced mainly using natural gas asraw material, mainly including partial oxidation and steam conversion ofnatural gas. Partial oxidation of natural gas is a relativelyenergy-consuming method, which consumes a lot of oxygen or air as feedgas. If a catalyst is not used, the reaction temperature must be reachedup to a temperature ranging from 1300 to 1400° C. Even if a catalyst isused, the temperature of catalytic bed is about in a range from 900 to1000° C. and the reaction need be carried out in high pressure (3.0MPa), which is demanding for the resistance of equipment to hightemperature and high pressure. In intermittent process of steamconversion of natural gas, the highest temperature is as high as 1300°C. It is an energy-intensive process. In continuous process of steamconversion of natural gas, although energy consumption is lower, therestill are strict requirements for the resistance of equipment to hightemperature and high pressure. And whether it is in intermittent processor in continuous process, the equipment corrosion by steam in rawmaterial gas at high temperature will affect the service life ofequipment, increasing the process cost. In these technologicalprocesses, there are technical problems including high reactiontemperature, high energy consumption, and strict requirements for theresistance of equipment to high temperature, high pressure and the like.Therefore, it is of great significance for industrial production ofsyngas to develop a production process without water and oxygen.

In addition to methane steam reforming and methane partial oxidation,methane reforming with carbon dioxide is a syngas production technologywhich has attracted more and more attention. The advantages of methanereforming with carbon dioxide are as follows: (1) Methane dry reformingwith carbon dioxide dispenses with oxygen and water, with lowerrequirements for equipment. (2) The ratio of H₂/CO is adjustable, whichis more suitable as the raw material of Fischer-Tropsch synthesis; andthe reaction can be carried out at a temperature above 650° C., and theenergy consumption is relatively low. (3) The source of carbon dioxideis extensive, which is cheaper than oxygen. The process simultaneouslyachieves the efficient use of methane and the carbon dioxide emissionreduction, with significant economic benefits and environmentalbenefits. Carbon dioxide is the end product of efficient utilization ofcoal and its downstream products. It is an important content of cleancoal utilization how to realize the recycling of carbon dioxide and makewaste profitable. The process is beneficial to reduce the total amountof carbon dioxide in the atmosphere and reduce the environmentalpressure caused by greenhouse gases, providing an effective method forNational emission reduction.

It is the key to develop low cost catalysts with high activity, highselectivity and high stability in order to activate and orientedconverse methane and carbon dioxide molecules which are inert active.

SUMMARY OF THE INVENTION

According to an aspect of the present application, a catalyst isprovided in order to solve the problem that in high temperaturereaction, the existing supported metal catalysts is apt to be sinteredand coked leading to catalyst deactivation. As a high temperature stablecatalyst for methane reforming with carbon dioxide, the catalyst can beused to produce syngas, realizing the emission reduction and recyclingof carbon dioxide. Under atmospheric pressure and at 800° C., thesupported metal catalyst with hierarchical pores shows excellentcomprehensive catalytic performance. In addition to high activity andgood selectivity, the catalyst has high stability, especially highresistance to sintering and carbon deposition.

The catalyst includes a support and an active component dispersed on/inthe support; wherein the support is at least one selected from inorganicoxides and the support contains macropores and mesopores;

wherein the active component includes an active element; and the activeelement contains an iron group element which is at least one selectedfrom ferrum, cobalt, nickel.

Preferably, the active element contains nickel.

Preferably, the average pore size of the macropores is greater than 50nm, and the average pore size of the mesopores is in a range from 1 nmto 50 nm.

Preferably, the average pore size of the macropores is in a range from 1μm to 2 μm. Preferably, the average pore size of the mesopores is in arange from 5 nm to 15 nm. Preferably, the specific surface area of thesupport is in a range from 100 m²/g to 350 m²/g.

Compared with traditional mesoporous supports, there is a coordinatingfunction between the support and the active component which makes theactive component homogeneously dispersed and strongly loaded in/on thesupport, avoiding the sintering of active component metal particles inthe process of catalytic reaction, restraining the formation of carbondeposition and prolonging the catalyst life. Inorganic oxides with theabove-mentioned macropores and mesopores all can be used as the supportof the catalyst in the present application, to solve the problem of hightemperature sintering and carbon deposition, prolonging the life of thecatalyst. Preferably, the support is at least one selected fromaluminium oxides, silicon oxides, titanium oxides, zirconium oxides.

As a preferred embodiment, the active element contains a noble metalelement. The noble metal element is at least one selected from gold,silver, ruthenium, rhodium, palladium, osmium, iridium, platinum.Further preferably, the noble metal element is at least one selectedfrom platinum, ruthenium, gold, rhodium.

The synergy between noble metals and non-noble metals (iron group metal)makes the catalysts containing both noble metals and iron group metalspossess more excellent overall catalytic performance than the catalystonly containing iron group metals. On the one hand, the introduction ofnoble metals active component is beneficial to the dispersion ofnon-noble metal components in the support, the further reduction ofparticle size of active metal component and the increase of the numberof active sites, thus improving the catalytic conversion rate. On theother hand, the decrease of the metal particle size in the activecomponent can increase the interaction of metal-support and improve thehigh temperature stability of the catalyst.

Preferably, the weight percentage content of the active component in thecatalyst is in a range from 1% to 15%; and the weight percentage contentof the active component is calculated according to the weight percentagecontent of the active element in the catalyst. Further preferably, theweight percentage content of the active component in the catalyst is ina range from 3.5% to 9%; and the weight percentage content of the activecomponent is calculated according to the weight percentage content ofthe active element in the catalyst.

Preferably, the lower limit of the weight percentage content of irongroup element belonging to the active element in the catalyst isselected from 1.0%, 1.5%, 1.76%, 2.0%, 2.76%, 3.0%, 3.5%, 3.84%, 4.0%,4.09%, 4.05%, 4.12%, 4.16%, 4.18%, 4.5%, 4.74%, 4.8% or 4.9%, and theupper limit is selected from 5.0%, 5.1%, 5.41%, 5.45%, 6.24%, 6.49%,7.0%, 8.0%, 9.0% or 10%; and the weight percentage content of iron groupelement in the catalyst is calculated according to the weight percentagecontent of the sum total of all the active iron group elements containedin the catalyst. Further preferably, the weight percentage content ofiron group element belonging to the active element in the catalyst is ina range from 1% to 10%. Still further preferably, the weight percentagecontent of iron group element belonging to the active element in thecatalyst is in a range from 3% to 6%.

Preferably, the lower limit of the weight percentage content of noblemetal element belonging to the active element in the catalyst isselected from 0.1%, 0.2%, 0.24%, 0.29%, 0.3%, 0.31%, 0.33%, 0.35%,0.37%, 0.38%, 0.39%, 0.40%, 0.42%, 0.43%, 0.45%, 0.5%, 0.54%, 0.55%,0.6%, 0.7%, 0.8% or 0.9%, and the upper limit is selected from 1.0%,1.07%, 1.5%, 2.0%, 2.5%, 2.93%, 3.0%, 3.5%, 4.0%, 4.5% or 5.0%; and theweight percentage content of noble metal element in the catalyst iscalculated according to the weight percentage content of the sum totalof all the noble elements contained in the catalyst. Further preferably,the weight percentage content of noble metal element belonging to theactive element in the catalyst is in a range from 0.1% to 5%. Stillfurther preferably, the weight percentage content of noble metal elementbelonging to the active element in the catalyst is in a range from 0.5%to 3%.

As an embodiment, the catalyst contains a modification componentdispersed on/in the support; and the modification component includes amodification element; and the said modification element is at least oneselected from alkali metal elements, alkaline earth metal elements, rareearth metal elements.

As an embodiment, the lower limit of the weight percentage content ofthe modification element in the catalyst is selected from 0.1%, 0.2%,0.3%, 0.36%, 0.4%, 0.5%, 0.6%, 0.7%, 0.77%, 0.8%, 0.85%, 0.87%, 0.9%,0.95% or 1%, and the upper limit is selected from 1.28%, 1.32%, 1.5%,2.0%, 2.07%, 2.11%, 2.5%, 2.65%, 2.8%, 3%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%,5.87%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5% or 9.0%; and the weightpercentage content of modification element in the catalyst is calculatedaccording to the weight percentage content of the sum total of all themodification elements contained in the catalyst.

Preferably, the weight percentage content of alkali metal element in thecatalyst is in a range from 0.1% to 10%. Further preferably, the lowerlimit of the weight percentage content of alkali metal element in thecatalyst is selected from 0.1%, 0.5%, 0.87%, 0.97% or 1.0%, and theupper limit is selected from 1.32%, 1.5%, 2.0%, 2.11%, 2.5%, 3.0%, 3.5%,4.0%, 4.5%, 4.85% or 5.0%. Still further preferably, the weightpercentage content of alkali metal element in the catalyst is in a rangefrom 0.1% to 5%.

Preferably, the weight percentage content of alkaline earth metalelement in the catalyst is in a range from 0.1% to 10%. Furtherpreferably, the lower limit of the weight percentage content of alkalineearth metal element in the catalyst is selected from 0.1%, 0.5%, 0.82%,0.95% or 1%, and the upper limit is selected from 2.0%, 2.11%, 2.5%,3.0%, 3.5%, 4.0%, 4.5%, 4.77%, 4.82% or 5.0%. Still further preferably,the weight percentage content of alkali metal element in the catalyst isin a range from 0.1% to 5%.

Preferably, the weight percentage content of rare earth metal element inthe catalyst is in a range from 0.1% to 10%. Further preferably, thelower limit of the weight percentage content of rare earth metal elementin the catalyst is selected from 0.1%, 0.2%, 0.3%, 0.36%, 0.5%, 0.6%,0.8% or 1.0%, and the upper limit is selected from 1.26%, 1.38%, 1.39%,1.4%, 1.5%, 2.0%, 2.11%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.07% or5.87%. Still further preferably, the weight percentage content of rareearth metal element in the catalyst is in a range from 0.1% to 6%.

The active component on/in the support exists as zero-valence metaland/or compound containing the active metal element. Preferably, theactive component on/in the support exists as zero valence metal.

The modification component on/in the support exists as compoundcontaining the modification element or zero-valence metal. Preferably,the modification component on/in the support exists as compoundcontaining the modification element.

The particle size distributions of the active component and themodification component are narrow, and the active component and themodification component are highly dispersed on/in the support withmacropores and mesopores.

Preferably, the particle size of the active component dispersed on/inthe support is in a range from 1 nm to 50 nm. Further preferably, theupper limit of the particle size of the active component dispersed on/inthe support is selected from 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm,45 nm or 50 nm, and the lower limit is selected from 1 nm, 5 nm or 10nm. Still further preferably, particle size of the active componentdispersed on/in the support is in a range from 1 nm to 15 nm.

Preferably, the particle size of the modification component dispersedon/in the support is in a range from 1 nm to 50 nm. Further preferably,the upper limit of the particle size of the modification componentdispersed on/in the support is selected from 15 nm, 20 nm, 25 nm, 30 nm,35 nm, 40 nm, 45 nm or 50 nm, and the lower limit is selected from 1 nm,5 nm or 10 nm. Still further preferably, the particle size of themodification component dispersed on/in the support is in a range from 1nm to 15 nm.

As a preferred embodiment, in the catalyst, the modification elementincludes a rare earth metal element.

As a preferred embodiment, in the catalyst, the active element includesa noble metal element and the modification element includes a rare earthmetal element.

As a further preferred embodiment, in the catalyst, the active elementis nickel and the modification element is a rare earth metal element.

As a still further preferred embodiment, in the catalyst, the activeelement is composed of platinum and nickel, and the modification elementis composed of erbium and potassium;

-   -   wherein the molar ratio of platinum, cobalt, erbium and        potassium is:

Pt:Co:Er:K=0.1%˜5%:1%˜10%:0.3%˜5%:0.2%˜5%.

According to another aspect of the present application, a method forpreparing the catalyst is provided, which includes at least the steps asfollows:

a) impregnating the support in a solution containing the active element;or impregnating the support in a solution containing the active elementand the modification element;

b) separating to obtain the impregnated solid obtained in step a) whichis dried, calcined under an air atmosphere and reduced by hydrogen toobtain the catalyst.

Preferably, in step a), the impregnation is an ultrasound impregnation;and the total immersion time is in a range from 24 hours to 96 hours,and accumulation of the ultrasonic time is in a range from 2 hours to 10hours.

Preferably, in step a), the ultrasound impregnation is an intermittentultrasound impregnation; and the total immersion time is in a range from36 hours to 60 hours, and accumulation of the ultrasonic time is in arange from 2 hours to 6 hours.

Preferably, in step b), the drying is conducted at a temperature rangefrom 60° C. to 200° C.

Preferably, in step b), the drying is vacuum drying conducted under atemperature range from 60° C. to 100° C. for a time range from 8 hoursto 10 hours.

Further preferably, in step b), the temperature is raised from roomtemperature to a calcination temperature at a heating rate range from 1°C./min to 10° C./min to calcine the impregnated solid for no less than 1hour, and the calcination temperature is in a range from 300° C. to 800°C.

Still further preferably, in step b) the temperature is raised from roomtemperature to a calcination temperature at a heating rate range from 1°C./min to 5° C./min to calcine the impregnated solid for a time rangefrom 2 hours to 4 hours, and the calcination temperature is in a rangefrom 500° C. to 700° C.

Preferably, in step b), the reduction by hydrogen is that thetemperature is raised from room temperature to a reduction temperatureat a heating rate range from 5° C./min to 20° C./min to reduce inhydrogen or a mixture of hydrogen and an inactive gas for no less than 1hour, and the reduction temperature is in a range from 600° C. to 1000°C.; and flow velocity of hydrogen or the mixture of hydrogen and theinactive gas is in a range from 20 mL/min to 80 mL/min.

Further preferably, in step b), the reduction by hydrogen is that thetemperature is raised from room temperature to a reduction temperatureat a heating rate range from 5° C./min to 15° C./min to reduce inhydrogen for a time range from 1 hour to 2 hours, and the reductiontemperature is in a range from 800° C. to 1000° C.; and the flowvelocity of hydrogen is in a range from 20 mL/min to 40 mL/min.Preferably, the inactive gas is at least one selected from nitrogen,inert gases. Further preferably, the inactive gas is at least oneselected from nitrogen, helium, argon.

According to another aspect of the present application, a method forproducing syngas by reforming methane with carbon dioxide is provided,wherein a material containing methane and carbon dioxide contacts with acatalyst to produce syngas; and the catalyst is at least one selectedfrom the above catalyst, the catalyst obtained using the above method.

Preferably, the reactants containing methane and carbon dioxide contactswith a catalyst to produce syngas at a reaction temperature from 600° C.to 900° C. and a reaction pressure from 0.1 MPa to 0.5 MPa; andin thereactants, the molar ratio of carbon dioxide to methane is as follows:carbon dioxide:methane is in a range from 0.5 to 2.

The beneficial effects of the present application include, but are notlimited to the following effects:

(1) The catalyst provided by the present application has hierarchicalsupports; the hierarchical supports bring in macropore channels whichincrease the diffusion rate and the mass transfer rate of the medium.The synergistic effect between the hierarchical channels and the activecomponents let the catalyst of the present application possess goodanti-sintering property and good anti-coking property at the same timewhen used in high temperature catalytic reactions.

(2) When modified by adding rare earth elements, the activity of thecatalyst provided in the present application can be effectively enhancedby adding the rare earth elements; the catalyst modified by rare earthelements brings higher catalytic conversion rate even in the case oflower active component load.

(3) When containing noble metals, except for applying iron group metals(at least one from iron, cobalt and nickel) as the first activecomponent, the catalyst provided by the present application alsointroduce noble metals as the second active component. The synergybetween noble metals and non-noble metals makes the catalysts containingboth noble metals and iron group metals possess more excellent overallcatalytic performance than the catalyst only containing iron groupmetals. On the one hand, the introduction of noble metals activecomponent is beneficial to the dispersion of non-noble metal componentsin the support, the further reduction of particle size of active metalcomponent and the increase of the number of active sites, thus improvingthe catalytic conversion rate. On the other hand, the decrease of themetal particle size in the active component can increase the interactionof metal-support and improve the high temperature stability of thecatalyst. Moreover, compared with catalyst simply containing noblemetals, the catalyst containing both iron group metals and noble metalslowers down the cost through the introduction of non-noble metals. Inconclusion, the catalyst containing both iron group metals and noblemetals has a better cost efficiency and possesses a good applicationprospect. The catalyst provided by the present application can befurther improved in the overall property through the introduction ofmodification components (alkali metal salts, alkaline-earth metal saltsor rare earth metal salts).

(4) The catalyst provided by the present application can be used as thehigh temperature stable catalyst in the reaction of reforming methanewith carbon dioxide, to produce syngas and thus realize the emissionreduction and reutilization of carbon dioxide. Under atmosphericpressure and at 800° C., it shows excellent overall catalytic property(activity, selectivity and stability) and has high cost efficiency, andthus possesses a very good application prospect.

DESCRIPTION OF THE FIGURES

FIG. 1 are SEM images of the section of hierarchical pored aluminiumoxide microsphere I; (a) is a 1100 times magnified SEM image; (b) is a35000 times magnified SEM image.

FIG. 2 are chromatography test results of the product of the reformingmethane reaction with carbon dioxide in which sample CAT-I-1 was used;(a) is the testing result from thermal conductivity detector (TCD); (b)is the testing result from flame ionization detector (FID).

FIG. 3 is the testing result of catalytic stability of sample CAT-I-1.

FIG. 4 are transmission electron microscope images of CAT-I-1 testedbefore and after the reaction; (a) is the transmission electronmicroscopy image of CAT-I-1 tested before the reaction; (b) is thetransmission electron microscopy image of CAT-I-1 tested after reactingfor 102 hours at 800° C.

FIG. 5 are figures comparing the catalytic activity between samplesCAT-II-1 and DCAT-II-1; (a) shows the conversion rate of carbon dioxide;(b) shows the conversion rate of methane.

FIG. 6 are chromatography test results of the product of the reformingmethane reaction with carbon dioxide in which sample CAT-II-1 was used;(a) is the testing result from thermal conductivity detector (TCD); (b)is the testing result from flame ionization detector (FID).

FIG. 7 is the testing result of catalytic stability of sample CAT-II-1.

FIG. 8 are transmission electron microscope images of CAT-II-1 testedbefore and after the reaction; (a) is the transmission electronmicroscopy image of CAT-II-1 tested before the reaction; (b) is thetransmission electron microscopy image of CAT-II-1 tested after reactingfor 102 hours at 800° C.

FIG. 9 are figures comparing the catalytic stability of samplesCAT-III-1, CAT-III-2 and CAT-III-17; wherein, (a) shows the relationshipof conversion rate of carbon dioxide and the reaction time; (b) showsthe relationship of conversion rate of methane and the reaction time.

FIG. 10 are transmission electron microscope images of sample CAT-III-1,sample CAT-III-17 and CAT-III-18; (a) is the transmission electronmicroscopy image of sample CAT-III-1, (b) is the transmission electronmicroscopy of sample CAT-III-17, (c) is the transmission electronmicroscopy image of sample CAT-III-18.

DETAILED DESCRIPTION OF THE EMBODIMENT

The present invention will be further illustrated in combination withthe following examples, but the present invention is not limited tothese examples. Meanwhile, though the examples provide some conditionsfor producing catalysts, it does not mean that all these conditions mustbe fully met to achieve the goal.

If there is no special notification, raw materials used in the examplesare purchased commercially and the devices are used with parametersettings recommended by the producer.

In the examples, SEM images of the samples are obtained using HITACHIS4800 scanning electron microscope; the transmission electron microscopeimages of the samples are obtained using FEI Company's F20 transmissionelectron microscope.

In the examples, the ultrasonic apparatus used for ultrasonic immersingis KQ300ED ultrasonic apparatus produced by Kunshan ultrasonic apparatuscorporation limited.

In the examples, the loading quantities of iron group elements, noblemetal elements, alkali metal elements, alkaline earth elements and rareearth elements are determined by plasma emission spectroscopy (ICP) onUltima 2 apparatus produced by HORIBA JY Corporation in France.

In the examples, the detection of the product generated in the reactionof preparing syngas from reforming methane with carbon dioxide iscarried out on SHIMAZU GC-2014 chromatograph (TDX-01 column).

In the examples, the specific surface area of the hierarchical aluminumoxide microsphere I is 197.91 m²/g, the average pore size of themacropores is 1.52 and the average pore size of the mesopores is 9.80nm; the specific surface area of the hierarchical aluminum oxidemicrosphere II is 200.45 m²/g, the average pore size of the macroporesis 1.61 μm, and the average pore size of the mesopores is 10.23 nm; thespecific surface area of the hierarchical aluminum oxide microsphere IIIis 213.09 m²/g, the average pore size of the macropores is 1.57 μm, andthe average pore size of the mesopores is 11.08 nm.

Example 1 Preparation and Characterization of the Catalyst

Certain amounts of active component metal salts and/or modificationcomponent were dissolved in 10 mL of water to form an aqueous solution,and then 5 g of support was added for ultrasonic impregnation, and thensolvent and surplus metal salts that had not been absorbed were filteredout. Support which absorbed the metal ion was dried under vacuum at 80°C. for 8 h, calcined under air atmosphere and reduced by hydrogen toobtain the catalyst.

Relationships between the number of the samples and specific experimentconditions, supports, raw materials are shown in Table 1.

TABLE 1 Metal Range of salts and Time of Percentage particle theultrasonic Calcination Hydrogen-Reduction composition size SampleSupport dosage impregnation Condition Condition of metals (nm) CAT-I-1hierarchical nickel impregnation calcination at high purity H₂, Ni: 4.5%10-45 pored acetate for 48 h; 600° C.for 4 h; reduction at aluminium (5intermittent heating rate: 900° C. for 4 h; oxide mmol) ultrasound 1°C./min heating rate: microsphere for 4 h 10° C. /min; I flow rate: 30mL/min CAT-I-2 hierarchical nickel impregnation calcination at highpurity H₂, Ni: 3.55% 10-40 pored acetate for 48 h; 600° C. 4 h;reduction at aluminium (2.5 intermittent heating rate: 900° C. for 4 h;oxide mmol) ultrasound 1° C./min heating rate: microsphere for 4 h 10°C. /min; I flow rate: 30 mL/min CAT-I-3 hierarchical nickel impregnationcalcination at high purity H₂, Ni: 5% 10-50 pored acetate for 48 h; 600°C.for 4 h; reduction at aluminium (7.5 intermittent heating rate: 900°C. for 4 h; oxide mmol) ultrasound 1° C./min heating rate: microspherefor 4 h 10° C. /min; I flow rate: 30 mL/min CAT-I-4 hierarchical nickelimpregnation calcination at high purity H₂, Ni: 10-45 pored acetate for48 h; 600° C. for 4 h; reduction at 4.4% aluminium (5 intermittentheating rate: 900° C. for 4 h; oxide mmol) ultrasound 1° C./min heatingrate: microsphere for 4 h 10° C. /min; I flow rate: 30 mL/min CAT-I-5hierarchical nickel impregnation calcination at high purity H₂, Ni:10-40 pored acetate for 24 h; 600° C. for 4 h; reduction at 4.3%aluminium (5 intermittent heating rate: 900° C. for 4 h; oxide mmol)ultrasound 1° C./min heating rate: microsphere for 10 h 10° C. /min; Iflow rate: 30 mL/min CAT-I-6 hierarchical nickel impregnationcalcination at high purity H₂, Ni: 10-50 pored acetate for 96 h; 600° C.for 4 h; reduction at 4.6% aluminium (5 intermittent heating rate: 900°C. for 4 h; oxide mmol) ultrasound 1° C./min heating rate: microspherefor 2 h 10° C. /min; I flow rate: 30 mL/min CAT-I-7 hierarchical nickelimpregnation calcination at high purity H₂, Ni: 10-50 pored acetate for48 h; 300° C. for 6 h; reduction at 4.5% aluminium (5 intermittentheating rate: 900° C. for 4 h; oxide mmol) ultrasound 5° C./min heatingrate: microsphere for 4 h 10° C. /min; I flow rate: 30 mL/min CAT-I-8hierarchical nickel impregnation calcination at high purity H₂, Ni:10-45 pored acetate for 48 h; 800° C. for 4 h; reduction at 4.5%aluminium (5 intermittent heating rate: 900° C. for 4 h; oxide mmol)ultrasound 10° C./min heating rate: microsphere for 4 h 10° C. /min; Iflow rate: 30 mL/min CAT-I-9 hierarchical nickel impregnationcalcination at high purity H₂, Ni: 10-40 pored acetate for 48 h; 600° C.for 4 h; reduction at 4.5% aluminium (5 intermittent heating rate: 600°C. for 10 h; oxide mmol) ultrasound 1° C./min heating rate: microspherefor 4 h 5° C. /min; I flow rate: 20 mL/min CAT-I-10 hierarchical nickelimpregnation calcination at high purity H₂, Ni: 10-50 pored acetate for48 h; 600° C. for 4 h; reduction at 4.5% aluminium (5 intermittentheating rate: 1000° C. for 2 h; oxide mmol) ultrasound 1° C./min heatingrate: microsphere for 4 h 20° C. /min; I flow rate: 80 mL/min CAT-I-11hierarchical nickel impregnation calcination at 30% H₂/70%N₂, Ni: 10-45pored acetate for 48 h; 600° C. for 4 h; mixed gas, 4.5% aluminium (5intermittent heating rate: reduction at oxide mmol) ultrasound 1° C./min900° C. for 4 h; microsphere for 4 h heating rate: I 10° C. /min; flowrate: 50 mL/min CAT-II-1 hierarchical nickel impregnation calcination athigh purity H₂, Ni: 10-35 pored acetate for 48 h; 600° C. for 4 h;reduction at 3.82% aluminium (5 intermittent heating rate: 900° C. for 4h; Er: oxide mmol) ultrasound 1° C./min heating rate: 2.05% microsphereerbium for 4 h 10° C. /min; II nitrate flow rate: 30 (1 mmol) mL/minCAT-II-2 hierarchical nickel impregnation calcination at high purity H₂,Ni: 10-30 pored acetate for 48 h; 600° C.for 4 h; reduction at 3.33%aluminium (5 intermittent heating rate: 900° C. for 4 h; Er: oxide mmol)ultrasound 1° C./min heating rate: 3.52% microsphere erbium for 4 h 10°C. /min; II nitrate flow rate: 30 (3 mmol) mL/min CAT-II-3 hierarchicalnickel impregnation calcination at high purity H₂, Ni: 10-25 poredacetate for 48 h; 600° C. for 4 h; reduction at 2.91% aluminium (5intermittent heating rate: 900° C. for 4 h; Er: oxide mmol) ultrasound1° C./min heating rate: 8.66% microsphere erbium for 4 h 10° C. /min; IInitrate flow rate: 30 (5 mmol) mL/min CAT-II-4 hierarchical nickelimpregnation calcination at high purity H₂, Ni: 10-30 pored acetate for48 h; 600° C. for 4 h; reduction at 3.76% aluminium (5 intermittentheating rate: 900° C. for 4 h; Er: oxide mmol) ultrasound 1° C./minheating rate: 2.13% microsphere erbium for 4 h 10° C. /min; II nitrateflow rate: 30 (1 mmol) mL/min CAT-II-5 hierarchical nickel impregnationcalcination at high purity H₂, Ni: 10-30 pored acetate for 48 h; 600° C.for 4 h; reduction at 3.45% aluminium (5 intermittent heating rate: 900°C. for 4 h; Ce: oxide mmol) ultrasound 1° C./min heating rate: 3.37%microsphere cerous for 4 h 10° C. /min; II nitrate flow rate: 30 (1mmol) mL/min CAT-II-6 hierarchical nickel impregnation calcination athigh purity H₂, Ni: 10-25 pored acetate for 48 h; 600° C. for 4 h;reduction at 2.04% aluminium (2.5 intermittent heating rate: 900° C. for4 h; Er: oxide mmol) ultrasound 1° C./min heating rate: 2.26%microsphere erbium for 4 h 10° C. /min; II nitrate flow rate: 30 (1mmol) mL/min CAT-II-7 hierarchical nickel impregnation calcination athigh purity H₂, Ni: 10-40 pored acetate for 48 h; 600° C. for 4 h;reduction at 5.63% aluminium (7.5 intermittent heating rate: 900° C. for4 h; Er: oxide mmol) ultrasound 1° C./min heating rate: 1.95%microsphere erbium for 4 h 10° C. /min; II nitrate flow rate: 30 (1mmol) mL/min CAT-II-8 hierarchical nickel impregnation calcination athigh purity H₂, Ni: 10-35 pored nitrate for 48 h; 600° C. for 4 h;reduction at 3.85% aluminium (5 intermittent heating rate: 900° C. for 4h; Er: oxide mmol); ultrasound 1° C./min heating rate: 2.01% microsphereerbium for 4 h 10° C. /min; II nitrate flow rate: 30 (1 mmol) mL/minCAT-II-9 hierarchical nickel impregnation calcination at high purity H₂,Ni: 10-30 pored acetate for 24 h; 600° C. for 4 h; reduction at 3.65%aluminium (5 intermittent heating rate: 900° C. for 4 h; Er: oxide mmol)ultrasound 1° C./min heating rate: 1.93% microsphere erbium for 10 h 10°C. /min; II nitrate flow rate: 30 (1 mmol) mL/min CAT-II-10 hierarchicalnickel impregnation calcination at high purity H₂, Ni: 10-45 poredacetate for 96 h; 600° C. for 4 h; reduction at 4.15% aluminium (5intermittent heating rate: 900° C. for 4 h; Er: oxide mmol) ultrasound1° C./min heating rate: 2.13% microsphere erbium for 2 h 10° C. /min; IInitrate flow rate: 30 (1 mmol) mL/min CAT-II-11 hierarchical nickelimpregnation: calcination at high purity H₂, Ni: 10-40 pored acetate 48h; 300° C. for 6 h; reduction at 3.85% aluminium (5 intermittent heatingrate: 900° C. for 4 h; Er: oxide mmol) ultrasound 5° C./min heatingrate: 2.02% microsphere erbium for 4 h 10° C. /min; II nitrate flowrate: 30 (1 mmol) mL/min CAT-II-12 hierarchical nickel impregnationcalcination at high purity H₂, Ni: 10-30 pored acetate for 48 h; 800° C.for 2 h; reduction at 3.91% aluminium (5 intermittent heating rate: 900°C. for 4 h; Er: oxide mmol) ultrasound 10° C./min heating rate: 2.10%microsphere erbium for 4 h 10° C. /min; II nitrate flow rate: 30 (1mmol) mL/min CAT-II-13 hierarchical nickel impregnation calcination athigh purity H₂, Ni: 10-35 pored acetate for 48 h; 600° C. for 4 h;reduction 3.85% aluminium (5 intermittent heating rate: 600° C. for 10h; Er: oxide mmol) ultrasound 1° C./min heating rate: 2.06% microsphereerbium for 4 h 5° C. /min; II nitrate flow rate: 20 (1 mmol) mL/minCAT-II-14 hierarchical nickel impregnation calcination at high purityH₂, Ni: 10-40 pored acetate for 48 h; 600° C. for 4 h; reduction at3.84% aluminium (5 intermittent heating rate: 1000° C. for 2 h; Er:oxide mmol) ultrasound 1° C./min heating rate: 2.03% microsphere erbiumfor 4 h 20° C. /min; II nitrate flow rate: 80 (1 mmol) mL/min CAT-II-15hierarchical nickel impregnation calcination at 30% H₂/70% N₂, Ni: 10-35pored acetate for 48 h; 600° C. for 4 h; mixed gas, 3.79% aluminium (5intermittent heating rate: reduction at Er: oxide mmol) ultrasound 1°C./min 900° C. for 4 h; 2.01% microsphere erbium for 4 h heating rate:II nitrate 10° C. /min; (1 mmol) flow rate: 50 CAT-III-1 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  5-15 poredacetate for 48 h; 600° C. for 4 h; reduction at 4.18% aluminium (5intermittent heating rate: 900° C. for 4 h; Pt: oxide mmol); ultrasound1° C./min heating rate: 0.43% microsphere platinum for 4 h 10° C. /min;III tetrachloride(0.5 flow rate: 30 mmol) mL/min CAT-III-2 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  1-10 poredacetate for 48 h; 600° C. for 4 h; reduction at 4.09% aluminium (5intermittent heating rate: 900° C. for 4 h; Pt: oxide mmol); ultrasound1° C./min heating rate: 0.38% microsphere platinum for 4 h 10° C. /min;Er: III tetrachloride flow rate: 30 0.36% (0.5 mmol); mL/min erbiumnitrate (0.5 mmol) CAT-III-3 hierarchical cobalt impregnationcalcination at high purity H₂, Co:  1-10 pored acetate for 48 h; 600° C.for 4 h; reduction at 4.05% aluminium (5 intermittent heating rate: 900°C. for 4 h; Pt: oxide mmol); ultrasound 1° C./min heating rate: 0.33%microsphere platinum for 4 h 10° C. /min; K: III tetrachloride flowrate: 30 0.87% (0.5 mmol); mL/min potassium nitrate (1 mmol) CAT-III-4hierarchical cobalt impregnation calcination at high purity H₂, Co: 1-10 pored acetate for 48 h; 600° C. for 4 h; reduction at 4.12%aluminium (5 intermittent heating rate: 900° C. for 4 h; Pt: oxidemmol); ultrasound 1° C./min heating rate: 0.29% microsphere platinum for4 h 10° C. /min; Mg: III tetrachloride(0.5 flow rate: 30 0.95% mmol);mL/min mganesium chloride (1 mmol) CAT-III-5 hierarchical cobaltimpregnation calcination at high purity H₂, Co:  1-5 pored acetate for48 h; 600° C. for 4 h; reduction at 4.16% aluminium (5 intermittentheating rate: 900° C. for 4 h; Pt: oxide mmol); ultrasound 1° C./minheating rate: 0.31% microsphere platinum for 4 h 10° C. /min; Er: IIItetrachloride flow rate: 30 0.86% (0.5 mmol); mL/min K: erbium 0.97%nitrate (1 Mg: mmol) 0.82% potassium nitrate (1 mmol); magnesiumchloride (1 mmol) CAT-III-6 hierarchical cobalt impregnation calcinationat high purity H₂, Co:  1-10 pored chloride for 48 h; 600° C. for 4 h;reduction at 1.76% aluminium (2 intermittent heating rate: 900° C. for 4h; Au: oxide mmol); ultrasound 1° C./min heating rate: 2.93% microspherechloroauric for 4 h 10° C. /min; III acid (3 flow rate: 30 mmol) mL/minCAT-III-7 hierarchical nickel impregnation calcination at high purityH₂, Ni:  1-10 pored acetate for 48 h; 300° C. for 6 h; reduction at4.736% aluminium (5 intermittent heating rate: 900° C. for 4 h; Pt:oxide mmol) ultrasound 5° C./min heating rate: 0.54% microsphereplatinum for 4 h 10° C. /min; III tetrachloride flow rate: 30 (1 mmol);mL/min CAT-III-8 hierarchical iron impregnation calcination at highpurity H₂, Fe:  1-10 pored nitrate for 48 h; 600° C. for 4 h; reductionat 2.76% aluminium (1 intermittent heating rate: 900° C. for 4 h; Ru:oxide mmol); ultrasound 1° C./min heating rate: 0.54% microsphereruthenium for 4 h 10° C. /min; III acetylacetonate flow rate: 30 (2mmol) mL/min CAT-III-9 hierarchical cobalt impregnation calcination at30% H₂/70% N₂, Co:  1-10 pored acetate for 48 h; 600° C. for 4 h; mixedgas, 4.02% aluminium (5 intermittent heating rate: reduction at Pt:oxide mmol); ultrasound 1° C./min 900° C. for 4 h; 0.42% microsphereplatinum for 4 h heating rate: Ni: III tetrachloride 10° C. /min; 1.39%(0.5 mmol); flow rate: 50 nickel mL/min acetate (2 mmol) CAT-III-10hierarchical cobalt impregnation calcination at 30% H₂/70% N₂, Co:  1-10pored acetate for 48 h; 600° C. for 4 h; mixed gas, 4.12% aluminium (5intermittent heating rate: reduction at Pt: oxide mmol); ultrasound 1°C./min 900° C. for 4 h; 0.37% microsphere platinum for 4 h heating rate:Ni: III tetrachloride 10° C. /min; 1.33% (0.5 mmol); flow rate: 50 La:nickel mL/min 5.87 acetate (2 mmol) lanthanum nitrate (6 mmol)CAT-III-11 hierarchical cobalt impregnation calcination at high purityH₂, Co:  1-10 pored acetate for 48 h; 600° C. for 4 h; reduction at4.03% aluminium (5 intermittent heating rate: 600° C. for 10 h; Pt:oxide mmol); ultrasound 1° C./min heating rate: 0.39% microsphereplatinum for 4 h 5° C. /min; Fe: III tetrachloride flow rate: 20 2.46%(0.5 mmol); mL/min iron nitrate (3 mmol) CAT-III-12 hierarchical cobaltimpregnation calcination at high purity H₂, Co:  1-10 pored acetate for48 h; 600° C. for 4 h; reduction at 3.23% aluminium (4 intermittentheating rate: 900° C. for 4 h; Pt: oxide mmol); ultrasound 1° C./minheating rate: 0.24% microsphere platinum for 4 h 10° C. /min; Fe: IIItetrachloride flow rate: 30 1.87% (1 mmol); mL/min K: iron 4.85% nitrate(2 mmol) potassium chloride (5 mmol) CAT-III-13 hierarchical cobaltimpregnation calcination at high purity H₂, Co:  1-10 pored acetate for48 h; 800° C. for 2 h; reduction at 3.93% aluminium (5 intermittentheating rate: 900° C. for 4 h; Pt: oxide mmol); ultrasound 10° C./minheating rate: 0.33% microsphere platinum for 4 h 10° C. /min; Fe: IIItetrachloride flow rate: 30 1.23% (0.5 mmol); mL/min Ni: iron 1.08%nitrate (1.5 mmol) nickel acetate (1 mmol) CAT-III-14 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  1-10 poredacetate for 48 h; 600° C. for 4 h; reduction at 2.75% aluminium (3intermittent heating rate: 1000° C. for 2 h; Pt: oxide mmol); ultrasound1° C./min heating rate: 1.07% microsphere platinum for 4 h 20° C. /min;Fe: III tetrachloride flow rate: 80 0.34% (2 mmol); mL/min Ni: iron0.75% nitrate Mg: (0.5 mmol) 4.77% nickel acetate (1 mmol) magnesiumnitrate (5 mmol) CAT-III-15 hierarchical iron impregnation calcinationat high purity H₂, Fe:  1-10 pored nitrate for 48 h; 600° C. for 4 h;reduction at 3.93% aluminium (6 intermittent heating rate: 1000° C. for2 h; Ru: oxide mmol) ultrasound 1° C./min heating rate: 0.75%microsphere Ruthenium for 4 h 20° C. /min; K: III acetylacetonate flowrate: 80 2.11% (0.2 mmol); mL/min potassium chloride (2 mmol) CAT-III-16hierarchical iron impregnation calcination at high purity H₂, Fe:  5-15pored nitrate for 48 h; 600° C. for 4 h; reduction at 3.93% aluminium (6intermittent heating rate: 1000° C. for 2 h; Rh: oxide mmol) ultrasound1° C./min heating rate: 0.36% microsphere rhodium for 4 h 20° C. /min;La: III chloride flow rate: 80 2.11% (0.5 mmol); mL/min lanthanumnitrate (2 mmol) CAT-III-17 hierarchical cobalt impregnation calcinationat high purity H₂, Co: 10-35 pored acetate for 48 h; 600° C. ° C.reduction at 4.42% aluminium (5 mmol); intermittent for 4 h; 900° C. for4 h; oxide ultrasound heating rate: heating rate: microsphere for 4 h 1°C./min 10° C. /min; III flow rate: 30 mL/min CAT-III-18 hierarchicalcobalt impregnation calcination at high purity H₂, Co: 10-40 poredacetate for 48 h; 600° C. ° C. reduction at 4.05% aluminium (5 mmol);intermittent for 4 h; 900° C. for 4 h; Er: oxide erbium ultrasoundheating rate: heating rate: 1.39% microsphere acetate for 4 h 1° C./min10° C. /min; III (1 mmol) flow rate: 30 mL/min CAT-III-19 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  5-30 poredacetate for48 h; 600° C. reduction at 4.26% aluminium (5 mmol);intermittent for 4 h; 900° C. for 4 h; La: oxide lanthanum ultrasoundheating rate: heating rate: 5.07% microsphere nitrate for 4 h 1° C./min10° C. /min; III (5 mmol) flow rate: 30 mL/min CAT-III-20 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  5-35 poredacetate for 48 h; 600° C. reduction at 4.07% aluminium (5 mmol);intermittent for 4 h; 900° C. for 4 h; K: oxide potassium ultrasoundheating rate: heating rate: 4.85% microsphere chloride for 4 h 1° C./min10° C. /min; III (5 mmol) flow rate: 30 mL/min CAT-III-21 hierarchicalcobalt impregnation calcination at high purity H₂, Co:  5-35 poredacetate for 48 h; 600° C. reduction at 4.36% aluminium (5 mmol);intermittent for 4 h; 900° C. for 4 h; Mg: oxide magnesium ultrasoundheating rate: heating rate: 4.82% microsphere chloride for 4 h 1° C./min10° C. /min; III (5 mmol) flow rate: 30 mL/min CAT-III-22 hierarchicalcobalt impregnation calcination at high purity H₂, Co: 10-40 poredsulfate for 48 h; 300° C. reduction at 2.85% aluminium (3 mmol);intermittent for 6 h; 900° C. for 4 h; oxide ultrasound heating rate:heating rate: microsphere for 4 h 5° C./min 10° C. /min; III flow rate:30 mL/min CAT-III-23 hierarchical cobalt impregnation calcination athigh purity H₂, Fe: 10-35 pored nitrate for 48 h; 600° C. reduction at4.63% aluminium (5 mmol) intermittent for 4 h; 900° C. for 4 h; oxideultrasound heating rate: heating rate: microsphere for 4 h 1° C./min 10°C. /min; III flow rate: 30 mL/min CAT-III-24 hierarchical ironimpregnation calcination at 30% H₂/70% N₂, Fe: 10-35 pored nitrate for48 h; 600° C. mixed gas, 3.89% aluminium (6 mmol) intermittent for 4 h;reduction at Ni: oxide nickel acetate ultrasound heating rate: 900° C.for 4 h; 1.24% microsphere (2 mmol) for 4 h 1° C./min heating rate: III10° C. /min; flow rate: 50 mL/min CAT-III-25 hierarchical ironimpregnation calcination at 30% H₂/70% N₂, Fe: 10-40 pored nitrate for48 h; 600° C. mixed gas, 4.79% aluminium (6 mmol) intermittent for 4 h;reduction at Co: oxide cobalt acetate ultrasound heating rate: 900° C.for 4 h; 1.24% microsphere (2 mmol) for 4 h 1° C./min heating rate: III10° C. /min; flow rate: 50 mL/min CAT-III-27 hierarchical ironimpregnation calcination at high purity H₂, Fe: 10-35 pored nitrate for48 h; 600° C. reduction at 2.04% aluminium (2.5 mmol) intermittent for 4h; 900° C. for 4 h; Co: oxide cobalt ultrasound heating rate: heatingrate: 1.97% microsphere acetate for 4 h 1° C./min 10° C. /min; Er: III(3 mmol); flow rate: 30 1.26% erbium mL/min nitrate (1 mmol) CAT-III-28hierarchical cobalt impregnation calcination at high purity H₂, Fe:10-35 pored acetate for 48 h; 800° C. reduction at 2.91% aluminium (3mmol) intermittent for 2 h; 900° C. for 4 h; Ni: oxide nickel ultrasoundheating rate: heating rate: 2.39% microsphere acetate for 4 h 10° C./min10° C. /min; K: III (3 mmol); flow rate: 30 1.32% potassium mL/minchloride (1 mmol) CAT-III-29 hierarchical iron impregnation calcinationat high purity H₂, Fe:  5-35 pored nitrate for 48 h; 600° C. reductionat 3.93% aluminium (6 mmol) intermittent for 4 h; 1000° C. for 2 h; Mg:oxide magnesium ultrasound heating rate: heating rate: 2.11% microspherechloride for 4 h 1° C./min 20° C. /min; Er: III (2 mmol); flow rate: 801.38% erbium mL/min nitrate (1 mmol)

Example 2 Characterization of the Samples

Scanning electron microscopes are used for the characterizations ofhierarchical pored aluminium oxide microsphere I, hierarchical poredaluminium oxide microsphere II and hierarchical pored aluminium oxidemicrosphere III. As the typical sample, the cross-sectional SEM imagesof the hierarchical pored aluminium oxide microsphere I were shown inFIG. 1. It can be seen that hierarchical pored aluminium oxidemicrospheres possess micron-sized macropores and nanopores. The SEMimages of hierarchical pored aluminium oxide microsphere II andhierarchical pored aluminium oxide microsphere III are similar with FIG.1.

Transmission electron microscope was used to observe the particle sizesof active components and modification components rare earth particles onthe catalyst. The results of the particle sizes are shown in Table 1.

ICP was used to determine the percentage contents of iron groupelements, noble metal elements, alkali metal elements, alkaline earthmetal elements and rare earth elements in the samples. The results areshown in Table 1.

Example 3 Catalytic Properties of Sample CAT-I-1˜CAT-I-11

0.2 g of catalyst CAT-I-1 was put into a fixed bed reactor with an innerdiameter of 1 cm, and reducted online by hydrogen. The temperature ofthe reactor was adjusted to the reaction temperature subsequently. Thereducing gas was switched to a mixed gas of CO₂ and CH₄, wherein N₂ wasused as an internal standard. The reacted gas was cooled down and thecontents of each substance therein were determined by gaschromatography. Conversions of CO₂ and CH₄ were calculated.

Relationships between reaction conditions and the conversions of CO₂ andCH₄ are shown in Table 2.

When the reaction condition was A, the chromatography results of thetail gas was shown in FIG. 2. It can be seen from FIG. 2 that, thecatalyst provided by the present application has good selectivity, andthe product was mainly consisted of hydrogen and carbon monoxide, whichare the major constituents of syngas.

TABLE 2 Conditions Composition Reaction for hydrogen and flow conditiononline rate of raw Reaction Reaction Conversion Conversion No. reductiongas temperature pressure rate of CO₂ rate of CH₄ A high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 82.52% 64.91% reduction at 47: 47: 6 800° C.for1 h; flow rate: 30 heating rate: mL/min 10° C./min; flow rate: 15mL/min B 80% H₂/20% CO₂: CH₄: N₂ = 800° C. 0.1 MPa 83.64% 65.57% N₂mixedgas, 47: 47: 6 reduction at flow rate: 30 850° C. for 2 h; mL/minheating rate: 20° C./min flow rate: 30 mL/min C high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 90.37% 38.28% reduction at 31: 62: 7 800° C.for 1 h; flow rate: 50 heating rate: mL/min 10° C./min; flow rate: 15mL/min D high purity H₂, CO₂: CH₄: N₂ = 800° C. 0.1 MPa 41.34% 92.46%reduction at 62: 31: 6 800° C. for 1 h; flow rate: 50 heating rate:mL/min 10° C./min; flow rate: 15 mL/min E high purity H₂, CO₂: CH₄: N₂ =600° C. 0.1 MPa 18.37%  8.41% reduction at 47: 47: 6 800° C. for 1 h;flow rate: 30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min Fhigh purity H₂, CO₂: CH₄: N₂ = 850° C. 0.1 MPa 92.97% 84.13% reductionat 47: 47: 6 800° C. for 1 h; flow rate: 30 heating rate: mL/min 10°C./min; flow rate: 15 mL/min G high purity H₂, CO₂: CH₄: N₂ = 800° C.0.5 MPa 93.65% 75.39% reduction at 47: 47: 6 800° C. for1 h; flow rate:30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min

Conversion rates of CO₂ and CH₄ are calculated by the following equationrespectively:

${{CO}_{2}\%} = {\frac{F_{{{CO}\; 2},{in}} - F_{{{CO}\; 2},{out}}}{F_{{{CO}\; 2},{in}}} \times 100\%}$${{CH}_{4}\%} = {\frac{F_{{{CH}\; 4},{in}} - F_{{{CH}\; 4},{out}}}{F_{{{CH}\; 4},{in}}} \times 100\%}$

wherein F_(CO2, in) and F_(CO2, out) are respectively volume flows ofCO₂ in the raw gas and reaction tail gas; F_(CH4, in) and F_(CH4, out)are respectively volume flows of CH₄ in the reactant and the product.

Under the same reaction conditions, catalyst CAT-I-2˜CAT-I-11 providedsimilar results as CAT-I-1, and the conversion rates of CO₂ and CH₄ varyin a range of ±10% on the basis of the difference in the preparationmethods of the catalysts.

Example 4 Evaluation on the Catalyst Stability of SamplesCAT-I-1˜CAT-I-11

0.2 g of catalyst CAT-I-1 was put into a fixed bed reactor with an innerdiameter of 1 cm. The evaluation on the catalyst stability is carriedout under the reaction condition A in Example 3, and the result is shownin FIG. 3. It can be seen from FIG. 3 that, CAT-I-1 possesses excellentstability under atmospheric pressure and at 800° C., and the conversionrates of carbon dioxide and methane nearly maintain unchanged within thefirst 100 hours of reaction.

Transmission electron microscope images of CAT-I-1 tested before andafter the reaction are shown in FIG. 4. FIG. 4(a) is the transmissionelectron microscopy image of CAT-I-1 tested before the reaction; FIG.4(b) is the transmission electron microscopy image of CAT-I-1 testedafter reacting for 102 hours at 800° C. It can be seen from FIG. 4 that,nickel particles, as the active component on the catalyst, nearly didnot change after the reaction and had not been sintered; moreover, nodeposited carbon was generated in the catalyst within 102 hours.

Under the same reaction conditions, the results of evaluation on thecatalyst stability of CAT-I-2˜CAT-I-11 are similar to that of CAT-I-I,and the conversion rates of carbon dioxide and methane nearly maintainunchanged within the first 100 hours. Transmission electron microscopyimages of samples CAT-I-2˜CAT-I-11 before and after 102 hours ofreaction at 800° C. show the similar comparison results as CAT-1-1. Thenickel particle had not been sintered, and no deposited carbon wasgenerated in the catalyst.

Example 5 Preparation of Catalyst DCAT-II-1

5 mmol of nickel acetate was dissolved in 10 mL water to form asolution, and 5 g of hierarchical pored aluminium oxide microsphere IIwas added. After being impregnated for 48 h (ultrasonic was conductedfor 4 h intermittently), water and surplus nickel acetate that had notbeen absorbed were filtered out. After being vacuum dried at 80° C. for8 h, aluminium oxide absorbed the nickel ion was calcinated at 600° C.for 4 h in air atmosphere (the heating rate was 1° C./min), followed byreduction for 4 h at 900° C. using high purity hydrogen (the heatingrate was 10° C./min). The obtained sample was denoted as catalystDCAT-II-1. The mass percentage content of nickel in DCAT-II-1 is 4.25%.

Example 6 Comparison on the Activity Between CAT-II-1 and DCAT-II-1

Each 0.2 g of catalyst samples CAT-II-1 and DCAT-II-1 was put into afixed bed reactor with inner diameter of 1 cm, and high purity H₂ with aflow rate of 5 mL/min was continuously introduced into the reactor, andthen the reactor was heated to 800° C. with a heating rate of 10° C./minand hydrogen online reduction of the catalyst was carried out for 1 h.30 mL/min of raw gas (molar ratio of CO₂:CH₄:N₂=47:47:6) was introduced,and the reaction pressure was kept at 0.1 MPa, and the temperature wasadjusted to 600° C., then the reaction temperature was raised graduallyto 850° C. with a heating rate of 10° C./min. The comparison of theconversion rates of carbon dioxide and methane on catalyst CAT-II-1 andDCAT-II-1 at different reaction temperature was shown in FIG. 5.

Mass percentage content of nickel in CAT-II-1 is 3.82%; mass percentagecontent of nickel in CAT-II-1 is 4.25%. It can be seen from FIG. 5 thatbeing introduced with modification rare earth elements, the catalystCAT-II-1 with a lower content of the active component, had a betterperform on the conversion rates of carbon dioxide and methane thanDCAT-II-1 with higher component content.

Example 7 Evaluation on the Catalytic Properties of SamplesCAT-II-1˜CAT-II-15

0.2 g of catalyst CAT-II-1 was put into a fixed bed reactor with aninner diameter of 1 cm, after hydrogen online reduction, the temperatureof the reactor was adjusted to the reaction temperature. The gas wasswitched to a mixed gas of CO₂ and CH₄, wherein N₂ was used as aninternal standard. The reacted gas was cooled down and the contents ofeach substance were determined by gas chromatography. Conversions of CO₂and CH₄ were calculated.

Relationships between reaction conditions and the conversions of CO₂ andCH₄ are shown in Table 3.

When the reaction condition was A, the chromatography results of thetail gas were shown in FIG. 6. It can be seen from FIG. 6 that, thecatalyst provided by the present application has good selectivity, andthe product was mainly consisted of hydrogen and carbon monoxide, whichare the major constituents of syngas.

TABLE 3 Conditions Composition Reaction for hydrogen and flow conditiononline rate of raw Reaction Reaction Conversion Conversion No. reductiongas temperature pressure rate of CO₂ rate of CH₄ A high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 83.15% 71.34% reduction at 47: 47: 6 800°C.for 1 h; flow rate: 30 heating rate: mL/min 10° C./min; flow rate: 15mL/min B 80% H₂/20% N₂ CO₂: CH₄: N₂ = 800° C. 0.1 MPa 85.23% 73.15%mixed gas, 47: 47: 6 reduction at flow rate: 30 850° C. for 2 h; mL/minheating rate: 20° C./min flow rate: 30 mL/min C high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 91.35% 39.61% reduction at 31: 62: 7 800° C.for 1 h; flow rate: 50 heating rate: mL/min 10° C./min; flow rate: 15mL/min D high purity H₂, CO₂: CH₄: N₂ = 800° C. 0.1 MPa 53.72% 89.23%reduction at 62: 31: 6 800° C. for 1 h; flow rate: 50 heating rate:mL/min 10° C./min; flow rate: 15 mL/min E high purity H₂, CO₂: CH₄: N₂ =600° C. 0.1 MPa 23.35% 15.81% reduction at 47: 47: 6 800° C. for 1 h;flow rate: 30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min Fhigh purity H₂, CO₂: CH₄: N₂ = 850° C. 0.1 MPa 93.25% 85.62% reductionat 47: 47: 6 800° C. for 1 h; flow rate: 30 heating rate: mL/min 10°C./min; flow rate: 15 mL/min G high purity H₂, CO₂: CH₄: N₂ = 800° C.0.5 MPa 92.34% 85.36% reduction at 47: 47: 6 800° C. for 1 h; flow rate:30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min

Conversion rates of CO₂ and CH₄ are calculated by the following equationrespectively:

${{CO}_{2}\%} = {\frac{F_{{{CO}\; 2},{in}} - F_{{{CO}\; 2},{out}}}{F_{{{CO}\; 2},{in}}} \times 100\%}$${{CH}_{4}\%} = {\frac{F_{{{CH}\; 4},{in}} - F_{{{CH}\; 4},{out}}}{F_{{{CH}\; 4},{in}}} \times 100\%}$

wherein F_(CO2, in) and F_(CO2, out) are respectively volume flows ofCO₂ in the raw gas and reaction tail gas; F_(CH4, in) and F_(CH4, out)are respectively volume flows of CH₄ in the reactant and the product.

Under the same reaction conditions, catalyst CAT-II-2˜CAT-II-15 providedsimilar results as CAT-II-1, and the conversion rates of CO₂ and CH₄vary in a range of ±10% on the basis of the difference in thepreparation methods of the catalysts.

Example 8 Evaluation on the Stability of Samples CAT-II-1˜CAT-II-15

0.2 g of catalyst CAT-II-1 was put into a fixed bed reactor with aninner diameter of 1 cm. The evaluation on the catalyst stability wascarried out under the reaction condition A in Example 7. The result isshown in FIG. 7. It can be seen from FIG. 7 that, the catalyst providedby the present application possesses excellent stability underatomospheric pressure and at 800° C., and the conversion rates of carbondioxide and methane nearly maintain unchanged within the first 100 hoursof reaction.

Transmission electron microscope images of CAT-II-1 tested before andafter the reaction are shown in FIG. 8. FIG. 8(a) is the transmissionelectron microscopy image of CAT-II-1 tested before the reaction; FIG.8(b) is the transmission electron microscopy image of CAT-II-1 testedafter reacting for 102 hours at 800° C. It can be seen from FIG. 8 that,nickel particles, the active component on the catalyst, nearly did notchange after the reaction and had not been sintered; moreover, nodeposited carbon was generated in the catalyst within 102 hours.

Under the same reaction conditions, the results of evaluation on thecatalyst stability of CAT-II-2˜CAT-II-15 are similar to that ofCAT-II-I, and the conversion rates of carbon dioxide and methane nearlymaintain unchanged within the first 100 hours. Transmission electronmicroscopy images of samples CAT-II-2˜CAT-I-15 before and after 102hours of reaction at 800° C. show the similar comparison results asCAT-II-1, the nickel particle had not been sintered and no depositedcarbon was generated in the catalyst.

Example 9 Evaluation on the Catalytic Properties of SamplesCAT-III-1˜CAT-III-2

0.2 g of catalyst CAT-III-1 was put into a fixed bed reactor with aninner diameter of 1 cm, after hydrogen online reduction, the temperatureof the reactor was adjusted to the reaction temperature. The reductiongas was switched to a mixed gas of CO₂ and CH₄, wherein N₂ was used asan internal standard. The reacted gas was cooled down and the contentsof each substance therein were determined by gas chromatography.Conversions of CO₂ and CH₄ were calculated.

Relationships between reaction conditions and the conversions of CO₂ andCH₄ are shown in Table 4.

TABLE 4 Conditions Composition Reaction for hydrogen and flow conditiononline rate of raw Reaction Reaction Conversion Conversion No. reductiongas temperature pressure rate of CO₂ rate of CH₄ A high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 88.43% 75.98% 800° C. 47: 47: 6 reduction 1 h;flow rate: 30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min B80% H₂/20% N₂ CO₂: CH₄: N₂ = 800° C. 0.1 MPa 87.98% 74.28% mixed gas,47: 47: 6 850° C. flow rate: 30 reduction 2 h; mL/min heating rate: 20°C./min flow rate: 30 mL/min C high purity H₂, CO₂: CH₄: N₂ = 800° C. 0.1MPa 93.87% 42.87% 800° C. 31: 62: 7 reduction 1 h; flow rate: 50 heatingrate: mL/min 10° C./min; flow rate: 15 mL/min D high purity H₂, CO₂:CH₄: N₂ = 800° C. 0.1 MPa 62.76% 92.98% 800° C. 62: 31: 6 reduction 1 h;flow rate: 50 heating rate: mL/min 10° C./min; flow rate: 15 mL/min Ehigh purity H₂, CO₂: CH₄: N₂ = 600° C. 0.1 MPa 29.90% 18.26% 800° C. 47:47: 6 reduction 1 h; flow rate: 30 heating rate: mL/min 10° C./min; flowrate: 15 mL/min F high purity H₂, CO₂: CH₄: N₂ = 900° C. 0.1 MPa 95.47%87.86% 800° C. 47: 47: 6 reduction 1 h; flow rate: 30 heating rate:mL/min 10° C./min; flow rate: 15 mL/min G high purity H₂, CO₂: CH₄: N₂ =800° C. 0.5 MPa 94.27% 86.73% 800° C. 47: 47: 6 reduction 1 h; flowrate: 30 heating rate: mL/min 10° C./min; flow rate: 15 mL/min

Conversion rates of CO₂ and CH₄ are calculated by the following equationrespectively:

${{CO}_{2}\%} = {\frac{F_{{{CO}\; 2},{in}} - F_{{{CO}\; 2},{out}}}{F_{{{CO}\; 2},{in}}} \times 100\%}$${{CH}_{4}\%} = {\frac{F_{{{CH}\; 4},{in}} - F_{{{CH}\; 4},{out}}}{F_{{{CH}\; 4},{in}}} \times 100\%}$

wherein F_(CO2, in) and F_(CO2, out) are respectively volume flows ofCO₂ in the raw gas and reaction tail gas; F_(CH4, in) and F_(CH4, out)are respectively volume flows of CH₄ in the reactant and the product.

Under the same reaction conditions, catalyst CAT-III-2˜CAT-III-29provided similar results as CAT-III-1, and the conversion rates of CO₂and CH₄ vary in a range of ±20% on the basis of the difference in thepreparation methods of the catalysts.

Example 10 Evaluation on the Stability of Samples CAT-III-1˜CAT-III-2

Each 0.2 g of sample catalysts CAT-III-1, CAT-III-2 and CAT-III-17 wereadded to fixed bed reactors with an inner diameter of 1 cm. Theevaluation was carried out under the reaction condition A in Example 9.

The stability test results of catalysts CAT-III-1, CAT-III-2 andCATA-III-17 are shown in FIG. 9 (a) and FIG. 9(b). It can be seen fromFIG. 9 that, CAT-III-1 and CAT-III-2, which contained noble metals andiron group metals in their active elements, maintain a relatively goodstability in the conversion rates of carbon dioxide and methane underatmospheric pressure and at 800° C. within 204 hours of the reaction.Those catalysts did not contain noble metals provided a slightly lowerstability. The stability of the catalyst:CAT-III-2>CAT-III-1>CAT-III-17, which means that the addition of thenoble metals improve the stability of the catalyst. At the same time,the data in FIG. 9(a) and FIG. 9(b) indicate that, except for theimprovement of the stability, the conversion rates of carbon dioxide andmethane are also significantly raised after the introduction of noblemetals to the catalyst. Furthermore, after modified by adding a smallquantity of rare earth elements, the conversion rates were also slightlyraised.

Example 11 the Effect of Adding Noble Metals

As the typical sample, the transmission electron microscopy image ofCAT-III-1 was shown in FIG. 10(a). It can be seen from FIG. 10 that, onthe catalyst containing noble metals, the metal particles have uniformsizes range from 5 nm to 15 nm, and the metal particles are disperseduniformly on/in the support. FIG. 10(b) and FIG. 10(c) are transmissionelectron microscopy images of CAT-III-17 and CA-III-18, respectively.Comparing FIG. 10(a)˜FIG. 10(c), it can be seen that, after adding rareearth elements to the non-noble metal catalyst, the particle size of theactive metal particle decreases; however, after adding noble metals, thereduction in the particle size was much more bigger than that of addingrare earth elements. This well explained the reason why the samplecatalysts containing noble metals provide a higher carbon dioxide andmethane conversion rates. Meanwhile, small sized metallic activecomponent particles have stronger interaction with the support, which isbeneficial for enhancing the high temperature catalytic stability of thecatalyst. Compared with adding modification component (such as rareearth elements), adding noble metal active component improved much morein the overall property of the iron group catalysts.

The foregoing is only several examples and preferred embodiments of thepresent application, and is not any kind of limit to the scope of thepresent application. However, it can be conceived that other variationsand modifications can be made without departing from the scope coveredby the claims of the present application, and all of these variationsand modifications fall into the scope of protection of the presentapplication.

1. A catalyst, which includes a support and an active componentdispersed on/in the support; wherein the support is at least oneselected from inorganic oxides and the support contains macropores andmesopores; wherein the active component includes an active element; andthe active element contains an iron group element which is at least oneselected from ferrum, cobalt, nickel; the average pore size of themacropores is greater than 50 nm, and the average pore size of themesopores is in a range from 1 nm to 50 nm; and the particle size of theactive component dispersed on/in the support is in a range from 1 nm to50 nm.
 2. The catalyst according to the claim 1, wherein the averagepore size of the macropores is in a range from 1 μm to 2 μm; the averagepore size of the mesopores is in a range from 5 nm to 15 nm; and thespecific surface area of the support is in a range from 100 m²/g to 350m²/g.
 3. The catalyst according to the claim 1, wherein the activeelement contains a noble metal element; and the noble metal element isat least one selected from gold, silver, ruthenium, rhodium, palladium,osmium, iridium, platinum.
 4. The catalyst according to the claim 1,wherein the weight percentage content of iron group element belonging tothe active element in the catalyst is in a range from 1% to 10%; and theweight percentage content of noble metal element belonging to the activeelement in the catalyst is in a range from 0.1% to 5%.
 5. The catalystaccording to the claim 1, wherein the catalyst contains a modificationcomponent dispersed on/in the support; and the modification componentincludes a modification element; and the modification element is atleast one selected from alkali metal elements, alkaline earth metalelements, rare earth metal elements.
 6. The catalyst according to theclaim 5, wherein particle size of the active component dispersed on/inthe support is in a range from 1 nm to 15 nm; and particle size of themodification component dispersed on/in the support is in a range from 1nm to 50 nm.
 7. The catalyst according to the claim 5, wherein theactive element is composed of platinum and nickel, and the modificationelement is composed of erbium and potassium; wherein the molar ratio ofplatinum, cobalt, erbium and potassium is:Pt:Co:Er:K=0.1%˜5%:1%˜10%:0.3%˜5%:0.2%˜5%.
 8. A method for preparing thecatalyst according to claim 1, which includes at least the steps asfollows: a) impregnating the support in a solution containing the activeelement; or impregnating the support in a solution containing the activeelement and the modified element; b) separating to obtain theimpregnated solid obtained in step a) which is dried, calcined under anair atmosphere and reduced by hydrogen to obtain the catalyst.
 9. Themethod according to claim 8, wherein in step a), the impregnation is anultrasound impregnation; and the total immersion time is in a range from24 hours to 96 hours, and accumulation of the ultrasonic time is in arange from 2 hours to 10 hours; and in step b), the drying is conductedat a temperature range from 60° C. to 200° C.
 10. The method accordingto claim 8, wherein in step b), the drying is vacuum drying conductedunder a temperature range from 60° C. to 100° C. for a time range from 8hours to 10 hours.
 11. (canceled)
 12. A method for producing syngas byreforming methane with carbon dioxide, wherein a reactant containingmethane and carbon dioxide contacts with a catalyst to produce syngas;the catalyst is at least one selected from the catalyst according toclaim.
 13. The method according to claim 12, wherein the reactantcontaining methane and carbon dioxide contacts with a catalyst toproduce syngas at a reaction temperature from 600° C. to 900° C. and areaction pressure from 0.1 MPa to 0.5 MPa; and in the reactant, themolar ratio of carbon dioxide to methane is as follows: carbondioxide:methane is in a range from 0.5 to
 2. 14. The catalyst accordingto the claim 3, wherein the weight percentage content of iron groupelement belonging to the active element in the catalyst is in a rangefrom 3% to 6%; and the weight percentage content of noble metal elementbelonging to the active element in the catalyst is in a range from 0.5%to 3%.
 15. The catalyst according to the claim 5, wherein the weightpercentage content of alkali metal element in the catalyst is in a rangefrom 0.1% to 10%; the weight percentage content of alkaline earth metalelement in the catalyst is in a range from 0.1% to 10%; and the weightpercentage content of rare earth metal element in the catalyst is in arange from 0.1% to 10%.
 16. The catalyst according to the claim 5,wherein the weight percentage content of alkali metal element in thecatalyst is in a range from 0.1% to 5%; the weight percentage content ofalkaline earth metal element in the catalyst is in a range from 0.1% to5%; and the weight percentage content of rare earth metal element in thecatalyst is in a range from 0.1% to 6%.
 17. The method according toclaim 8, wherein in step a), the ultrasound impregnation is anintermittent ultrasound impregnation; and the total immersion time is ina range from 36 hours to 60 hours, and accumulation of the ultrasonictime is in a range from 2 hours to 6 hours.
 18. The method according toclaim 8, wherein in step b), the temperature is raised from roomtemperature to a calcination temperature at a heating rate range from 1°C./min to 10° C./min to calcine the impregnated solid for no less than 1hour, and the calcination temperature is in a range from 300° C. to 800°C.
 19. The method according to claim 8, wherein in step b), thetemperature is raised from room temperature to a calcination temperatureat a heating rate range from 1° C./min to 5° C./min to calcine theimpregnated solid for a time range from 2 hours to 4 hours, and thecalcination temperature is in a range from 500° C. to 700° C.
 20. Themethod according to claim 8, wherein in step b), the reduction byhydrogen is that the temperature is raised from room temperature to areduction temperature at a heating rate range from 5° C./min to 20°C./min to reduce in hydrogen or a mixture of hydrogen and an inactivegas for no less than 1 hour, and the reduction temperature is in a rangefrom 600° C. to 1000° C.; and flow velocity of hydrogen or the mixtureof hydrogen and the inactive gas is in a range from 20 mL/min to 80mL/min.
 21. The method according to claim 8, wherein in step b), thereduction by hydrogen is that the temperature is raised from roomtemperature to a reduction temperature at a heating rate range from 5°C./min to 15° C./min to reduce in hydrogen for a time range from 1 hourto 2 hours, and the reduction temperature is in a range from 800° C. to1000° C.; and the flow velocity of hydrogen is in a range from 20 mL/minto 40 mL/min.